diff --git a/libitm/common.h b/libitm/common.h
index 14d0efb..b1ef2d4 100644
--- a/libitm/common.h
+++ b/libitm/common.h
@@ -54,6 +54,8 @@ namespace GTM HIDDEN {
 // cache lines that are not shared with any object used by another thread.
 extern void * xmalloc (size_t s, bool separate_cl = false)
   __attribute__((malloc, nothrow));
+extern void * xcalloc (size_t s, bool separate_cl = false)
+  __attribute__((malloc, nothrow));
 extern void * xrealloc (void *p, size_t s, bool separate_cl = false)
   __attribute__((malloc, nothrow));
 
diff --git a/libitm/util.cc b/libitm/util.cc
index afd37e4..48a1bf8 100644
--- a/libitm/util.cc
+++ b/libitm/util.cc
@@ -71,6 +71,18 @@ xmalloc (size_t size, bool separate_cl)
 }
 
 void *
+xcalloc (size_t size, bool separate_cl)
+{
+  // TODO Use posix_memalign if separate_cl is true, or some other allocation
+  // method that will avoid sharing cache lines with data used by other
+  // threads.
+  void *r = calloc (1, size);
+  if (r == 0)
+    GTM_fatal ("Out of memory allocating %lu bytes", (unsigned long) size);
+  return r;
+}
+
+void *
 xrealloc (void *old, size_t size, bool separate_cl)
 {
   // TODO Use posix_memalign if separate_cl is true, or some other allocation